In one aspect, this invention relates to the treatment of catalytic cracking catalysts with antimony compound(s) and at least one transition metal compound (so as to alleviate detrimental effects of metal deposits on the catalysts). In another aspect, this invention relates to the use of thus-treated catalysts in a catalytic cracking processes. In a further aspect, this invention relates to a process for catalytically cracking metal-containing oils with a catalyst which has been treated with antimony compound(s) and at least one transition metal compound.
The treatment of metal-contaminated zeolite-containing cracking catalysts with antimony compounds (for enhancing or restoring the activity of these catalyst and/or to increase the gasoline yield and/or to reduce hydrogen generation when these catalysts are employed in catalytic oil cracking processes) is well known under the term of "metals passivation" and has been described in the patent literature (e.g., in U.S. Pat. Nos. 3,711,422 and 4,025,458). Also described in the patent literature (e.g., in U.S. Pat. No. 4,183,803) are processes for catalytically cracking heavy oils to which an antimony compound has been added as a passivating agent. In the present invention, the passivating effect of antimony compounds is enhanced by the use of at least one additional compound of a transition metal.